Dividing data for multi-thread backup

ABSTRACT

Performing a backup is disclosed. One or more directories at a lowest level in a file directory associated with a storage is identified. The identified lowest level directories are divided into one or more directory groups. The backup of the directory groups is performed using parallel threads until all directory groups have been backed up.

BACKGROUND OF THE INVENTION

When using more than one backup data stream to perform a backup, the data set being backed up must be divided into saveset groups for processing by multiple parallel backup threads. Often it is desirable for the saveset groups to be of more or less equal size in order to evenly distribute the workload required to backup the data set evenly across the backup threads, e.g., to ensure that the parallel threads finish their work at about the same time so that no threads sit idle while there is still work to be done. Traditionally, determining equal sized saveset groups required executing a computationally expensive process to traverse a directory structure associated with the data set and exhaustively match individual data to a saveset group until the desired combination of saveset groups was formed. Therefore there exists a need to relatively quickly and efficiently divide up data to be backed up into saveset groups.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are disclosed in the following detailed description and the accompanying drawings.

FIG. 1 is a block diagram illustrating an embodiment of a backup environment.

FIG. 2 is a block diagram illustrating an embodiment of a content system.

FIG. 3 is a flow chart illustrating an embodiment of a process for performing a backup of a content system.

FIG. 4 is a block diagram illustrating an embodiment of a process for performing a backup of content system components.

FIG. 5 is a block diagram illustrating an embodiment of a process for restoring data.

FIG. 6 is a block diagram illustrating an embodiment of a process for displaying correlated backups.

FIG. 7 is a diagram of at least a portion of a display illustrating correlated component backups.

FIG. 8 is a flow chart illustrating an embodiment of a process for restoring a backup.

FIG. 9 is a diagram illustrating an embodiment of a file directory structure.

FIG. 10 is a flow chart illustrating an embodiment of a process for performing backup using threads and/or multiple independent software processes.

DETAILED DESCRIPTION

The invention can be implemented in numerous ways, including as a process, an apparatus, a system, a composition of matter, a computer readable medium such as a computer readable storage medium or a computer network wherein program instructions are sent over optical or electronic communication links. In this specification, these implementations, or any other form that the invention may take, may be referred to as techniques. A component such as a processor or a memory described as being configured to perform a task includes both a general component that is temporarily configured to perform the task at a given time or a specific component that is manufactured to perform the task. In general, the order of the steps of disclosed processes may be altered within the scope of the invention.

A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The scope of the invention is limited only by the claims and the invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.

Dividing a data set for backup in parallel, e.g., by multiple threads in the same or separate software processes, is disclosed. In some embodiments, known characteristics of the directory structure and/or data set are used to divide a data set relatively quickly into savesets of more or less the same size, without walking the entire directory structure. For example, it is the characteristic of some content management systems that files and/or other items of content are stored in a directory structure having four and only four levels, with all of the files residing in the fourth level. In some embodiments, a worklist of the lowest level directories is generated and divided up, e.g., by the number of lowest level directories, to create savesets of more or less equal size to be backed up in parallel.

FIG. 1 is a block diagram illustrating an embodiment of a backup environment. Content system 102, backup server 104, client 108, and backup administrator console 110 are connected together through network 106. Network 106 comprises a public or private network and/or combination thereof, for example an Ethernet, serial/parallel bus, intranet, Internet, NAS, SAN, LAN, WAN, and other forms of connecting multiple systems and/or groups of systems together. Client 108 accesses data associated with content system 102. For example, client 108 reads, saves, modifies, and/or searches data stored in a storage area associated with content system 102. Content system 102 is associated with data to be backed up using backup server 104. In some cases, client 108 desires to access the data to be backed up while a backup of the data in content system 102 is being performed. The data associated with content system 102 is stored one or more storage areas of content system 102 and/or on a remote storage area associated with content system 102. In some embodiments, the data to be backed up includes managed content that must be backed up in a consistent manner with metadata associated with the managed content. Backup server 104 backups at least a portion of data associated with content system 102. Data to be backed up from content system 102 is received by backup server through network 106 and/or another data communication path between backup server 104 and content system 102. For example, a SAN (storage area network) between backup server 104 and content system 102 is used. Backup admin console 110 is used configure backup server 104. In some embodiments, backup admin console 110 and client 108 exist together in a single system. In some embodiments, backup server 104 and content system 102 exist together in a system. Any number of backup servers, contents systems, backup admin consoles, and clients may exist.

FIG. 2 is a block diagram illustrating an embodiment of a content system. In some embodiments, content system 200 is included in content system 102 of FIG. 1. Content system 200 includes content server 202, FTI (Full Text Index) 204, DB (Database) 206, and SA (Storage Area content) 208. Content server 202 manages/controls access, configuration, and data contained in FTI 204, DB 206 and SA 208. Content server 202 may manage other storage in content system 200 or a remote storage not contained in content system 200. SA 208 includes one or more data files stored in a file system. For example, content files (e.g, word processing documents) created by a user are stored in SA 208. In some embodiments, SA 208 comprises multiple physical storage area that are logically combined together. In various embodiments, data versioning information is stored in SA 208. For example, when a new version of an old file is stored, the new version is saved as a new file rather than replacing the old version. DB 206 includes metadata associated with data stored in SA 208. The metadata includes one or more of the following: document version information, document owner information, and folder and directory information. In the example shown, information associated with DB 206 is at least in part stored in a database format. A database entry includes metadata information and an identifier associated with corresponding data in SA 206. In some embodiments, metadata associated with data in SA 208 is at least in part stored in a format other than a database. For example, an index data and/or a log data is used. FTI 204 includes an index of at least a portion of data contained in SA 208. FTI 204 can be used to locate data in SA 208 through a search query. For example, a search engine uses index data of FTI 204 to locate desired data in SA 208. In some embodiments, data in SA 208 is indexed to create/update search data associated with FTI 204. In some embodiments, FTI 204 is not implemented in content system 200. In various embodiments, content system 200 includes other logical and/or physical storage components. For example, install and configuration data is associated with content system 200. In some embodiments, at least a portion of FTI 204, DB 206, and/or SA 208 is stored together in a single physical file system. In some embodiments, FTI 204, DB 206, and/or SA 208 is stored across more than one physical storage.

Traditionally, backing up content system 200 requires placing content system 200 offline in order to guarantee content system 200 is in a consistent state for backup. For example, if backup of content server 202 was performed without any guarantee of consistency, a backup of DB 206 can include a reference to a data that a related backup of SA 208 does not contain because the reference was created in between the backup of the SA 208 and the backup of DB 206. While content system 200 is offline, users are unable to access content system 200 until the backup is complete and content system 200 placed back online. When traditionally performing the backup, FTI 204, DB 206, and SA 208 are manually backed up individually. Performing the individual manual component backups can be tedious, especially to devise a workload to continually achieve efficient backup performance. When restoring data from backup, it can be difficult browse, unify, and/or correlate the separate backups of the components. Attempting to restore only a portion of data in the backups can pose challenges of locating relevant data in the various backup components. It is desirable for a process of backing up content system 200 to be automated, efficient, consistent, and configurable while being transparent to a user of the system.

FIG. 3 is a flow chart illustrating an embodiment of a process for performing a backup of a content system. In some embodiments, the content system includes content system 200 of FIG. 2. At 302, configuration preferences are received. Receiving configuration preferences may include one or more of the following: accessing a configuration file, using a predetermined default configuration for an unspecified configuration, using a system configuration data, and accepting command-line input from a user and/or an administrator for a configuration. Examples of configurations include one or more of the following: source data configuration, destination backup data configuration, system configuration, user access configuration, backup consistency configuration, security configuration, and specification of one or more backup tools/utilities/scripts. At 304, an indication of a backup to be performed is received. In some embodiments, the indication includes a specification of a portion of data to be backed up in a content system. For example, only content data associated with a specific storage area is specified for backup. In some embodiments, the specification of data to be backed up is specified using configuration preferences. In various embodiments, the indication includes a request for initiation of a backup process. The backup may be performed periodically, on a prescribed basis, and/or substantially concurrent with a received indication. At 306, a live backup of content system components is performed in a manner that enables the system to be restored in a consistent state. In some embodiments, the live backup is performed in accordance with the received configuration parameters. In some embodiments, a component backup is performed as a snapshot backup that does not require traversal of a directory structure associated with the component. In some embodiments, a component backup is performed as a direct file copy. In some embodiments, a component backup can be performed using one or more various backup methods. Performing the live backup does not render the content system inaccessible by a user for the entire backup process. In some embodiments, restoring data to a consistent state includes restoring data to the system in a state recoverable by the system. For example, a content system is restored to a consistent state even if the system contains an inconsistency when the inconsistency is known by the system, the inconsistency is tolerated by the system, the inconsistency is recoverable by the system, and/or the inconsistency will not cause an error in the system. The inconsistency, in some embodiments, is tolerated if the inconsistency was generated within a specified amount of time in between component backups during a backup session.

FIG. 4 is a block diagram illustrating an embodiment of a process for performing a backup of content system components. In some embodiments, the process of FIG. 4 is included in 306 of FIG. 3. At 402, FTI component is quiesced. In some embodiments, the FTI component is FTI 204 of FIG. 2. Quiescing a component includes preparing the component for creating a consistent backup state. For example, updates are not allowed to the component but reads are allowed. In some embodiments, quiescing is associated with performing one or more operations to ensure intra-component consistency. In some embodiments quiescing a storage component includes performing one or more following: flushing one or more buffers associated with the storage component, disabling updates to the component, and logging transactions associated with the component. In various embodiments, the type of operations associated with performing quiescing is configurable. For example, configuration parameters in 302 of FIG. 3 may specify the type of operations and/or configuration associated with the operations performed during quiescing. At 404, SA component is quiesced. In some embodiments, the SA component is SA 208 of FIG. 2. At 406, the FTI component is backed up. In various embodiments, the type of backup method used to back up the FTI component is configurable and/or specified by configuration preference in 302 of FIG. 3. At 408, DB component is quiesced. In some embodiments, the DB component is DB 206 of FIG. 2. At 410, DB component is backed up. In various embodiments, the type of backup method used to back up the DB component is configurable and/or specified by configuration preference in 302 of FIG. 3. In some embodiments, a database backup tool/utility/script is used to perform the DB backup. The database backup utility may be a third party backup database utility. At 412, DB component is unquiesced. In some embodiments, unquiescing a component includes performing one or more of the following: re-enabling updates, ending hot backup transaction logging, and implementing changes requested to the component while quiesced. At 414, the SA component is backed up. In various embodiments, the type of backup method used to back up the SA component is configurable and/or specified by configuration preference in 302 of FIG. 3. In some embodiments, the SA component backup is initiated within a prescribed or indicated amount of time from unquiescing the DB component. The time constraint may guarantee a tolerable level of consistency in the created backup of the components. At 416, the SA component is unquiesced. At 418, the FTI component is unquiesced.

In some embodiments, at least a portion of the order of the process of FIG. 4 is important in ensuring the backup is created in a consistent state. For example, in a consistent backup, the SA component backup may contain data not referenced by the DB component backup, but the DB component backup may not reference data not contained in the SA component backup. To ensure such a consistency, the DB component must be backed up before the SA component. In some embodiments, the DB backup is initiated after the FTI backup. In such a case, data associated with the FTI backup will only reference data referenced by metadata in the DB backup. The order of the backup process, in some embodiments, is dependent upon one or more characteristics of a storage component and/or a content system. In various embodiments, amount of time between and/or taken during the process portions of FIG. 4 is important in ensuring the backup is created in a consistent state. For example, the backup of the SA component must be initiated within the de-facto standard five minutes after the unquiescing of the DB component to ensure the amount of data present in the SA component backup not referenced by the DB component backup is within a tolerated level. The order of process portions shown in FIG. 4 is merely an example. Various ordering that guarantees consistency in the created backup exists. In some embodiments, the FTI is unquiesced after the SA component is backed up

FIG. 5 is a block diagram illustrating an embodiment of a process for restoring data. In some embodiments, the data is restored to content system 200 of FIG. 2 using component backups created at least in part using the process of FIG. 4. At 502, an indication of a desired recovery is received. In some embodiments, the indication includes initialization of a backup restore process. At 504, available backup/restore points are displayed and/or determined. In some embodiments, the backup/restore points include one or more groups of related backups. For example, a restore point includes a FTI, a DB, and a SA component backups associated with a singe backup session. In various embodiments, the backup/restore points are organized by backup creation times. At 506, a selection of a backup/restore point to be restored is received. In some embodiments, the selection is automatic. For example, when a user specifies a time of a desired restore point, a backup/restore point is automatically determined. At 508, the selected backup/restore point is restored. In some embodiments, only a portion of data associated with a restore point is selected and restored.

FIG. 6 is a block diagram illustrating an embodiment of a process for displaying correlated backups. In some embodiments, the process of FIG. 6 is included in 504 of FIG. 5. At 602, a time frame is determined. In some embodiments, determining the time frame includes determining a time value and/or a range of time values. In various embodiments, the time frame is user defined and/or predetermined. At 604, component backups from the time frame are determined. In some embodiments, determining the component backups includes locating one or more component backups created in the determined time frame. At 606, the determined component backups are correlated. In some embodiments, correlating the component backups include associating together related backups and/or component backups created in the same backup session. The backup component correlation can be preprocessed and/or performed during backup recovery. For example, while component backups are created (e.g., the process of FIG. 4), the component backups are stored together with metadata correlating the component backups. Examples of the correlation metadata include one or more of the following: a unique point-in-time backup timestamp, a list of related component backup instances, pointers to a backup storage index, and backup/restore parameter settings. This correlation metadata can be used when restoring component backups to determine correlated component backups. At 608, the correlated backups are displayed as a related set. In some embodiments, at least a portion of information associated with the displayed set and/or data contained in a component backup of the displayed set is browseable by a user.

FIG. 7 is a diagram of at least a portion of a display illustrating correlated component backups. In some embodiments, display portion 700 is associated with the display in 504 of FIG. 5 and/or 608 of FIG. 6. In the display example shown, display portion 700 includes two sets of correlated component backups. Component backups are correlated by backup sessions. The backup sessions are associated with a timestamp indicating a backup session creation time. The session listings include a listing of a FTI backup instance, a DB backup instance, and a SA backup instance. Each listing of the component instance may include a display of component backup creation time and/or other data associated with the component backup. In some embodiments, correlated component backups are displayed using a command line prompt. In some embodiments, at least a portion of data contained in a listed component backup can be displayed by selecting the listed component backup.

FIG. 8 is a flow chart illustrating an embodiment of a process for restoring a backup. In some embodiments, the process of FIG. 8 is included in 508 of FIG. 5. At 802, a first component is restored. Restoring a first component includes using a component backup to restore the first component to a specified restore point. At 804, if it is determined that not all components have been restored, at 806, a next component is restored, and the process returns to 804. At 804, if it is determined that all components have been restored, at 810, process ends. The order of the component restoration may be preconfigured, specified by a configuration, or dependent upon characteristics of the components and/or a system associated with the components.

In some cases, backing up a large data set using a single backup stream can be inefficient. In some embodiments, component backups are performed using more than one backup data stream. Each backup data stream is associated with a thread that backs up one workload group. Data to be backed up is divided into one or more efficient workload groups. In some embodiments, the workload groups are efficient if the amount of processing required to backup each workload group is similar. In some embodiments, data to be backed up is not divided into workload groups if the size of the data to be backed up is smaller than a prescribed or indicated size. The size may be preconfigured or dynamically determined using information associated with the backup. In some embodiments, the size includes a maximum size per workload group.

FIG. 9 is a diagram illustrating an embodiment of a file directory structure. In some embodiments, directory structure 900 is associated with SA 208 of FIG. 2 and the SA in 414 of FIG. 4. Directory structure 900 includes a root directory level and three subdirectory levels with files contained in the lowest level (deepest level away from the root) directory. In some embodiments, directory structure 900 is associated with one or more constraints. The constraints include one or more of the following: maximum, minimum, and/or specified number of subdirectory levels; maximum, minimum, and/or specified number of subdirectories in a directory; maximum, minimum, and/or specified number of files in a directory; and specified to contain content files only in the lowest level directories. In some embodiments, the constraints are not limitations but instead a characteristic resulting from the particular way a content management or other system is configured to organize and store data. In the example shown, directory structure 900 contains a specified number of levels, and content files are stored in the lowest level directory, wherein each lowest level directory can contain at most 256 files. By using one or more constraints in various embodiments, dividing the directory structure into groups for backup can be more easily performed. For example, constraints are used to encourage a balanced directory tree structure that can be divided into groups of equal workload size by dividing a single directory level. In some embodiments, the constraints enable a directory structure to be divided without traversing the entire directory structure. In some embodiments, the constraints enable a directory structure to be divided into one or more efficient workload groups on the directory level rather than the level of individual files. For example, by constraining the maximum number of files and/or the maximum size of files in a directory, even the largest directory does not have to be split between workload groups because the largest directory is constrained to never contain too many files and/or because the size of the directory is constrained to be never too large for a single workload group. Files in directory structure 900 are divided into workload groups 902, 904, 906, and 906. Each group contains two lowest level directories that may each contain up to 256 files. In other embodiments, each group contains more than two lowest level directories. In some embodiments, the size of the files in the groups are at least in part used to determine efficient workload the groups. Each group is backed up by a single backup stream. One or more backup streams are run in parallel.

FIG. 10 is a flow chart illustrating an embodiment of a process for performing backup using threads and/or multiple independent software processes. In some embodiments, the process of FIG. 10 is included in 414 of FIG. 4. In some embodiments, the process of FIG. 10 is associated with directory structure 900 of FIG. 9. At 1002, a worklist of lowest level storage area directories is generated. In some embodiments, the worklist includes a list of files and directory paths associated with the files. In some embodiments, generating the worklist captures in a single consistent state, a frozen list of storage area directories and files to be backed up. In some embodiments, the worklist includes only a portion of files in a storage area. For example, the portion is associated with an incremental backup of files and directories that have changed since the last backup. At 1004, the worklist is divided into one or more savesets. In some embodiments, dividing the worklist includes determining saveset portions of the worklist in manner that the amount of processing required to backup each saveset is similar. In some embodiments, the number of files included in a saveset and/or the size of the saveset is determined at least in part using one or more of the following: a preconfigured value, a configuration value, a configuration preference specified in 302 of FIG. 3, the size of the worklist, and the number files/directories in the worklist. In some embodiments, one or more constraints on a directory structure associated with the worklist enable the division of the worklist to be performed in an efficient manner. At 1006, backup threads are run in parallel until all savesets have been backed up. The maximum number of backup threads run together at any one time may be predetermined and/or dynamically configured. In some embodiments, the number of threads run in parallel is determined using or one or more of the following: a preconfigured value, a configuration value, a configuration preference specified in 302 of FIG. 3, the size of the worklist, the number files/directories in the worklist, and characteristics of one or more systems running the threads.

Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, the invention is not limited to the details provided. There are many alternative ways of implementing the invention. The disclosed embodiments are illustrative and not restrictive. 

What is claimed is:
 1. A method of performing a backup, comprising: identifying one or more directories at a lowest level in a file directory associated with a storage using a processor, wherein the storage communicates with the processor via an interface, and wherein the file directory is constrained to grow in a balanced manner; dividing the identified lowest level directories into one or more directory groups based at least in part on a determination that the total size of the identified lowest level directories is greater than a threshold size using a processor; and performing the backup of the directory groups using parallel threads until all directory groups have been backed up using a processor, wherein the backup is performed without traversing the entire file directory and wherein the number of parallel threads used to perform the backup is determined using one or more of the following: a preconfigured value, a configuration value, a configuration preference, the number of lowest level directories that have been identified, and characteristics of one or more systems running the parallel threads.
 2. A method as recited in claim 1, wherein the file directory includes a content storage area root directory.
 3. A method as recited in claim 1, wherein the amount of processing required to backup each directory groups is similar.
 4. A method as recited in claim 1, wherein each of the parallel threads is associated with a different backup data stream.
 5. A method as recited in claim 1, wherein the file directory is constrained to include a maximum, a minimum, or a specified number of subdirectories in a directory of the file directory.
 6. A method as recited in claim 1, wherein the file directory is constrained to include a maximum, a minimum, or a specified number of subdirectory levels.
 7. A method as recited in claim 1, wherein the file directory is constrained to include a maximum, a minimum, or a specified number of files in a directory of the file directory.
 8. A method as recited in claim 1, wherein the file directory is constrained to only include content files in the lowest level directory.
 9. A method as recited in claim 1, wherein each of the one or more directory groups is constrained to be less than, equal to, or less than or equal to a preconfigured or an indicated maximum size per workload group.
 10. A method as recited in claim 9, wherein the size is associated with a maximum data size one of the parallel threads is configured to process, and the number of files is associated with a maximum number of files one of the parallel threads is configured to process.
 11. A method as recited in claim 9, wherein the size is determined at least in part using one or more of the following: the number of the identified lowest level directories.
 12. A method as recited in claim 1, wherein identifying the one or more directories at the lowest level includes identifying files and directories that have been modified or created since a previous backup.
 13. A system for performing a backup, comprising: a processor configured to identify one or more directories at a lowest level in a file directory associated with a storage, wherein the file directory is constrained to grow in a balanced manner, divide the identified lowest level directories into one or more directory group based at least in part on a determination that the total size of the identified lowest level directories is greater than a threshold size, and perform the backup of the directory groups using parallel threads until all directory groups have been backed up, wherein the backup is performed without traversing the entire file directory and wherein the number of parallel threads used to perform the backup is determined using one or more of the following: a preconfigured value, a configuration value, a configuration preference, the number of lowest level directories that have been identified, the size of the identified lowest level directories, and characteristics of the system; and an interface coupled to the processor for communicating with the storage; an interface coupled to the processor for communication with the storage.
 14. A system as recited in claim 13, wherein the amount of processing required to backup each of the one or more directory groups is similar.
 15. A system as recited in claim 13, wherein each of the one or more directory groups is constrained be less than, equal to, or less than or equal to a preconfigured or an indicated maximum size per workload group.
 16. A system as recited in claim 15, wherein the size is associated with a maximum data size one of the parallel threads is configured to process, and the number of files is associated with a maximum number of files one of the parallel threads is configured to process.
 17. A system as recited in claim 15, wherein the size is determined at least in part using one or more of the following: the number of the identified lowest level directories.
 18. A system as recited in claim 13, wherein the file directory includes a content storage area root directory.
 19. A system as recited in claim 13, wherein each of the parallel threads is associated with a different backup data stream.
 20. A system as recited in claim 13, wherein the file directory is constrained to include a maximum, a minimum, or a specified number of subdirectories in a directory of the file directory.
 21. A system as recited in claim 13, wherein the file directory is constrained to include a maximum, a minimum, or a specified number of subdirectory levels.
 22. A system as recited in claim 13, wherein the file directory is constrained to include a maximum, a minimum, or a specified number of files in a directory of the file directory.
 23. A system as recited in claim 13, wherein the file directory is constrained to only include content files in the lowest level directory.
 24. A system as recited in claim 13, wherein identifying the one or more directories at the lowest level includes identifying files and directories that have been modified or created since a previous backup.
 25. A computer program product for performing a backup, the computer program product being embodied in a computer readable storage medium and comprising computer instructions for: identifying one or more directories at a lowest level in a file directory associated with a storage, wherein the file directory is constrained to grow in a balanced manner; dividing the identified lowest level directories into one or more directory groups, based at least in part on a determination that the total size of the identified lowest level directories is greater than a threshold size; and performing the backup of the directory groups using parallel threads until all directory groups have been backed up, wherein the backup is performed without traversing the entire file directory and wherein the number of parallel threads used to perform the backup is determined using one or more of the following: a preconfigured value, a configuration value, a configuration preference, the number of lowest level directories that have been identified, and characteristics of one or more systems running the parallel threads. 